There’s roughly $8 trillion sitting in US money market funds. That’s not a typo. It’s a mountain of cash that’s been earning steady yields while investors waited for a reason to take more risk. According to BlackRock’s Rick Rieder, Trump’s Iran deal just provided that reason.
Rieder, BlackRock’s Chief Investment Officer of Global Fixed Income, pointed to the redeployment of capital from money market funds as a primary driver behind the recent surge in US equities. The logic is straightforward: when geopolitical risk drops, investors get braver. And when $8 trillion worth of investors get braver all at once, markets move fast.
The numbers behind the rally
Following Trump’s announcement of a tentative deal with Iran and the cancellation of proposed military strikes, US stock markets responded with conviction. The Dow climbed approximately 2% in a single session. The S&P 500 gained around 1.8%. The Nasdaq led the pack, jumping roughly 2.5%.
The rally makes more sense when you zoom out. US money market fund assets had been sitting near record highs, stabilizing around $8.17 trillion by April 2026. That figure represents an enormous pool of capital that had been parked on the sidelines, collecting yields while investors navigated tariff uncertainty, inflation concerns, and geopolitical anxiety.
